Recently, Lord May, a former president of the royal society and chief scientific adviser to the government, a self proclaimed atheist who says that he experienced an "inverse epiphany" at the age of 11, suggested that "God" might be needed to evoke an appropriate response to the ecological challenges currently facing humanity.

It is after all a perfectly reputable scientific way of proceeding to posit a hypothesis involving the existence of an unseen entity without which it is difficult to understand how the system being studied actually coheres. The "Higgs boson" is an example of just such an entity in the science which is being explored in the super collider in Geneva.

His remarks were made against the backcloth of a competitive auction in ecological doom on the part of some of our leading collapse gurus. Look at the Guardian website if you want examples.

Our country cannot simply be described as religious but Lord May's remarks point to the possibility that we are also entering a post secular period in which our perspective on the world is being refashioned in response to contemporary economic and environmental challenges and in which the search for a more holistic understanding of reality is rendering the rather flatland, reductionist descriptions of the recent past increasingly unsatisfying.

If the reference to God is edited out of our perspective then the world simply becomes a theatre of human willing. We come to regard ourselves as gods and our wills as sovereign. We no longer experience ourselves as participants in an animated universe but as detached exploiters of mere matter. Dominance is substituted for connectedness in our relations with the world around us. Choice becomes the highest good and not what we choose.

Jesus Christ "the icon of God", as it says inour second lesson, came in the form of a servant to convey the truth that the first step in becoming a human being is to refuse to be a little god – the theme of that marvellous chant from the letter of St Paul to the Philippians.

St Paul invites us to a great humility which must embrace a care for the frail and the poor of the earth and a detestation of every form of slavery and oppression. Genuine conversion to the way of Jesus Christ consists in turning away from deifying our own will; turning away from life as a consumer of the world and turning towards being a communicant; a citizen and a contemplative.

But it must be confessed that the atheists of the beginning of the modern period when this Cathedral was being built had a point. God seemed to be the underwriter of regimes throughout Europe where the many were compelled to bend to the will of the one who ruled. The God who supported tyranny was of course very far from the God and Father of Our Lord Jesus Christ but atheism appeared to be the gateway to political and personal freedom.

That of course was then and our situation now is very different. Many people as heirs of the Enlightenment which deposed the ancien regime throughout Europe have nevertheless clung to the belief that we could have Christian ethics without Christian faith.

One of the many virtues of the 19th century atheist Friedrich Nietzsche, the subject of Giles Fraser's PhD studies, was that he hated the Christian faith for what it was – a devotion to the ethics of compassion. He hated the Christian faith for what he saw as its enfeebling solicitude for the weak, the outcast and the infirm. Nietzsche knew that the disappearance of the Christian God would lead to a new set of values.

We have witnessed in the experiments of the political religions of the 20th century, Communism and National Socialism, attempts to explore just what those values might be in practice.

But the serious consequences of atheism are still largely hidden from our contemporaries and indeed we are all caught up in a society shaped by the sovereignty of human willing and choice untrammelled by any higher good.

The prophet/poets have been trying to describe the world which we have created but their message still has to sink in. TS Eliot's poem The Waste Land, published soon after the First World War in 1922 is one of the genuinely prophetic statements of the 20th century. Now after half a century of the consumerism, which has replaced the discredited political religions, we have entered not a metaphorical wasteland but a real one in which we are drowning in our own rubbish.

Increasing concern about the condition of our wasteland is among the contemporary signs that Lord May is right to detect a shift into a post secular mode in which our perspective on the world will be revised.

Will the church in these new circumstances be enabled to become what it was intended to be – a school of relating in which God meets us and draws us into a communion with him and with one another and revises our understanding of what is valuable in life through his human expression Jesus Christ? Will the church become a foretaste of a new way of being in the world in which we become increasingly aware that loving our neighbour today involves a care for the Creation and care for vulnerable communities of those least able to adapt to the economic and environmental changes that are occurring?

It is undeniable there has been a certain loss of nerve in the church, even an excessive desire to entertain rather than insist on a radically different way of life. But this Cathedral and its Institute is one of the places where we can with seriousness explore the consequences of the great crisis of the 21st century: an interlocking crisis in which denying God; despoiling the earth and diminishing humanity are an anti-trinity which we are called upon to unmask and against which we are called together to struggle, as members of the body of Christ.

This is a place where we are not afraid to reason and we are not ashamed to worship and to adore. May God bless you Giles as you set about your new work in name of Jesus Christ, the very image of God. Amen.